Comparing motion controllers...

[JW1977]

Ok, im gonna do that...
To bad, the IP-M is just right for all other reasons... Thinking about a way to do the homing without "twisting" the gantry.
Would it be possible to simply switch of the slaved motor each time you would want to home? To let one motor home that axis? Would that solve the problem?

[JAZZCNC]

Ok, im gonna do that...
To bad, the IP-M is just right for all other reasons... Thinking about a way to do the homing without "twisting" the gantry.
Would it be possible to simply switch of the slaved motor each time you would want to home? To let one motor home that axis? Would that solve the problem?

The IP-M will home the slaved axis but only using one switch. What needs to happen is for both motors to de-couple from being slaved together so while homing are independant of each other again and look for a switch of there own. Provided the switches are aligned this ensures each side is level and gantry is square again. Just having one switch whether that be moving one or two motors still won't straighten the gantry if twisted.

There is another crude but very affective way to ensure gantry is square and that is to bump up to hard stops which you know set the gantry square.

[Boyan Silyavski]

Pokeys57CNC can do all that,and generally i consider it much better option price wise or having in mind all possible options. If only CSLABS were not so dumb to make that slaving happen, which sure is a minor thing if they wanted to.

[JW1977]

Is there any obvious flaws with the Pokeys57 compared to the IP-M?
Does it have onboard BOB?

[Boyan Silyavski]

Is there any obvious flaws with the Pokeys57 compared to the IP-M?
Does it have onboard BOB?

Dean has both running so he can say best of all whats the deal.

Yes, its all in one.

I chose Pokeys for my big machine and have done still some test runs so can not speak much for the moment. The only obvious lack of something is the metal enclosure. Not that this should concern you . All else i see it better than 4 axis CSMIO. Especially as possibilities for upgrade later.



Bumping steppers at end stops is ok also and perfectly acceptable for non production machine.


What is not acceptable for me is their stubbornness and as i am also stubborn, i would not buy,endorse or recommend their board especially when there are cheaper and according to me better possibilities on the market.

[JW1977]

1 – Can’t stop thinking if it would be possible to install a second switch anyway? Or is that what you just said?
Connected so that the signal that keeps the gantry moving continues until both switches have broken the circuit.
It’s not the proper way to think but I’m new to this and I guess if it would be that simple, it would have been done right?

2 – To install 2 reference “pieces” from where the gantry position on each side can be measured.
So once in a while after homing the gantry I can twist one of the screws manually to set the gantry square and then turn it on again.
Would that work?

3 – I could let both ballscrews be driven from the same motor but I guess that would require a belt and with that I would loose some of the precision.

4 – What is the downside of squaring it the crude way besides that it feels… Crude?

5 – Would it help a bit if I choose 400 step motors instead of 200?

[Clive S]

3 – I could let both ballscrews be driven from the same motor but I guess that would require a belt and with that I would loose some of the precision.

This is one of the standard ways of doing this and has been proved to work well. If you look through the forum there are many cases where it has been done this way.

Installing a second switch as your point (1) will not work. Point (2) Will work as Jazzcnc has already said (but it is not an elegant way of doing it). Not sure what you mean in point (5) it has nothing to do with the homing sequence

[komatias]

To answer your last point,

When you set up your stepper drives system, you should set the drivers to microstep. That will make them run smoother and also allow you to have better resolution of angle. 10-16 microsteps is good depending on what resolutions you really want.

[JW1977]

When i looked at stepper motors i found motors with different step angles.
0.9° - 400 steps/revolution
1,8° - 200 steps/revolution

Im thinking that if i choose the one with the higher resolution Everything will be better...?
Allthough ive got a feeling its not that simple...

[JW1977]

Not sure what you mean in point (5) it has nothing to do with the homing sequence

I thought that if i choose a motor with a higher resolution it will only go half as much distance every time the motor "bumps" the wrong way...